Act as ECG Center for the Aspirin-Myocardial Infarction Study (AMIS) in the Secondary Prevention of Coronary Artery Disease. Participate in the development annd implementation of a standard protocol and a manual of operations for a double blind study to determine whether or not the regular administration of aspirin to people who have had a documented myocardial infarction will result in a significant reduction in total mortality over a three year period of follow-up.